Hear this word, you cows of Bashan on Mount Samaria, you women who oppress the poor and crush the needy and say to your husbands, “Bring us some drinks!” Amos 4:1 [NIV]
"Even if the cows of Bashan are the finest around, it is doubtful any woman would consider being compared to one a compliment! We must remember that Amos has been a herdsman, and he is familiar with these animals. Obviously, he sees something in the women of Israel that reminds him of them. Perhaps it is their size—all these women care about is filling their bellies. Perhaps it is their careless and callous attitudes.
Cattle are known to have a difficult time keeping within the bounds of their pasture, trampling anyone weaker and smaller who happens to get in their way. Or perhaps it is a combination of both. It seems these women have an unquenchable passion for pampering and pleasure, no matter what the cost, no matter who is in their way. This is completely unacceptable to a God who promises to satisfy those who help the needy (Isa 58:6-11)."
(General Editor Jean E. Syswerda, NIV Women of Faith Study Bible, Zondervan Publishing House, Grand Rapids, Mischigan, 2001, pg 1494)
Bashan was a rich pastureland where the needs and wants of cattle were easily met. Possibly the prophet's comparison of the women to "cows" is a type that compares to those Isaiah mentioned who "trampled" the courts of the Temple.
"When you come to appear before Me, Who has required this from your hand, To trample My courts? Isaiah 1:12 NKJV
In that instance, the Israelites being addressed were comparable to beasts (of both sexes) in that they cared only for their personal comfort- i.e. eating and sleeping and procreating. Those things took precedence over their faithfulness in keeping covenants and treasuring up thoughts of their Creator.